As is well known, tar sand or crude oil sand deposits are sands that are impregnated with crude/heavy oil also known as bitumen. Crude oil sands are typically overlain by various types of overburden media such as for example, muskeg, clay, soil and gravel. Existing systems of extracting bitumen from crude oil sand deposits utilize similar practices to those employed in strip mining of coal. As a result, these systems are heavily reliant on excavating shovels, draglines, trucks, gnawing/crushers or sizers to break down large lumps of crude oil sands to form crushed amassed aggregates. The crushed amassed aggregates are then transported to an extraction plant at some distance away for further processing. Alternatively, the crushed amassed aggregate are turned into slurry and transported to the extraction plant by cycloid feeders (also known as hydro-transport).
At the extraction plant, the bitumen is separated from sand and other media and upgraded for processing. The partially de-oiled sand residue (also known as tailings) if loose, is transported by truck to a tailing pond. If the de-oiled same residue is in slurry form, the residue is pumped by pipeline to the tailing pond.
These existing practices for extracting crude oil sands and recovering bitumen require vast amounts of energy and thus, contribute to excessive greenhouse gas production. These existing extraction practices also place extensive abrasive wear and tear on the processing equipment being used. Back-up machinery on stand-by is therefore often required to replace damaged equipment or components leading to additional expense. In addition, mining during the winter months is problematic owing to the freezing of the crude oil sands. These factors make existing practices for extracting bitumen from crude oil sands inefficient.
Currently, existing bitumen extraction practices require two (2)-tons of crude oil sands to recover one (1) barrel of oil and the process releases into the atmosphere more than ninety (90) Kg of greenhouse gases per barrel of recovered oil. In addition, up to five (5) barrels of contaminated wastewater per barrel of recovered oil are generated. The wastewater is typically dumped into accumulation sites with the wastewater eventually leaching into ground water. As will be appreciated from the above, the environmental consequences of existing crude oil sand extraction practices will clearly continue to violate Canada's commitments to the Kyoto Protocol to reduce greenhouse gas emissions by 6% by the year 2012.
Because the mining of crude oil sands using present day systems is a costly and inefficient process, there exists a need for more efficient and reliable systems. It is therefore an object of the present invention to provide a novel method, apparatus and system for separating bitumen from crude oil sands.